GEN 06:06 And it repented the Lord that he had made man on the earth, and it grieved him at heart.?

If He knew what we would do, why did it upset Him when we did it? I am a Christian, but I don't get it all.... The Ark was 525 ft long, 88 ft wide and 53 ft tall. Would all current and past species fit? I'm uming the fish and aquatic mammals fended for themselves. Did many current species evolve from a mother breed? Was humanity and the creatures confined to very small area on the planet at that time? The number of species very small? I also wonder about the sons of God coming in unto the daughters of man and breeding giants. Can you provide some insight please. As a Christian, am I wrong for asking questions like this? I feel horrible. I understand that worrying about the small things is not the best thing to be doing. Learning to love should be the focus. I just wonder. The more I visit this site, the more my faith wavers. It should hold strong in the storm. I am not liking this. Not a bit. I would like to hear Drake's council.